Mechanics of Sleep
I went through most of my life with just one rule when it came to sleep – as long as I got at least 4 hours, I’d be okay. For long periods of time, I actually averaged 4 hours (I kept track, believe it or not – yeah, a bit of a geek, I know). One particularly drawn-out, stressful time in my life provided me with just 3 hours of sleep per night, 5 nights out of 7. This was also a period during which I put on a substantial amount of weight.
On those days when I only got 4 hours, I lived on caffeine. I’d drink between 12 – 14 cups of strong coffee every day. I had to – otherwise, I couldn’t stay awake. I remember one particular night – and yes, I only ever did this once – I went 3 days without sleeping. By 3pm on the 4th day, I actually passed out. My brain had hit the wall and literally switched off. It took me about 2 weeks to recover.
Part of the problem was that I had no idea how important sleep actually was for me – and I didn’t really know how much sleep I actually needed. I thought I was okay with 4 hours, although I knew I was a bit tired. I believed that you could get your body used to only 4 hours sleep. At least, those were the old wives’s tales I’d heard. It wasn’t until just a couple of years ago that I began to learn differently, by looking at some of the research being done into sleep.
What Happens When We Sleep?
The short answer to that is – lots. Everybody has heard of REM sleep, or Rapid Eye Movement, where you dream your dreams at night. But REM sleep is just part of the whole sleep cycle. This text below is from Scienceline:
Before that dream-heavy period [of REM], though, we undergo Non-Rapid Eye Movement, or NREM, sleep, which takes up 75 percent of sleep time and is divided into four stages.
Stage 1 finds us dozing off, with our brain waves and muscle activity slowing down. You witness this very light sleep when the airplane passenger next to you suddenly jerks his leg and sends your five-dollar cocktail flying.
In Stage 2 usually comprising about half of sleep time, Stage 2 means a calmer brain wave pattern and no eye movements. Breathing slows and body temperature drops slightly. A person in Stage 2 has lost touch with his surroundings but can easily be shaken awake.
By Stages 3 and 4, though, waking someone up probably requires an annoying alarm. Breathing slows even more into a rhythm. Blood pressure and body temperature drop again and muscles relax. These two similar stages are called “slow wave sleep,” with the slowest of all brain waves.
This is the restorative, deep sleep we crave when we’re tired. Scientists believe that much of the body’s regenerative work, like protein building and hormone release, happens at this stage.
About 90 minutes after falling asleep, REM sets in and hypes up the slow wave sleep into a state that’s very close to being awake, with brain waves of the same speed or even faster. Most but not all dreams occur in this phase.
The heart beats quickly, blood pressure rises, eyes dart around and breathing becomes rapid and shallow. The body is more or less paralyzed; arm, leg and facial muscles might twitch, but the body won’t move. REM can last from five to 30 minutes.
After REM, NREM starts again. The 90- to 110-minute cycle of these two phases repeats four to six times per night. As the night progresses, the time spent in REM increases and deep sleep decreases so that when the rooster crows, it’s almost all Stage 1, Stage 2 and REM sleep.
In Part 4, we’ll look at how sleep actually benefits our bodies – what chemicals are produced while we slumber, and how we try, often unknowingly, to compensate during the day when we notice them missing.
Tell us about your sleep experience. Do you have trouble getting enough sleep?
- Sleep Stages (everydayhealth.com)
- Dream States: A Peek into Consciousness (scientificamerican.com)
- Sleepyti.me Helps To Calculate The Best Time To Sleep And To Wake Up (techie-buzz.com)